Viscosimeter



Aug. 27, 1935. R, Powls 2,012,551,"

VISCOSIMETER 4 Filednec. 11, 1933 2 sheets-sheet 1 ,2f l i/ Y kind inwhich errors in viscosity readings. result- Patented Aug. 21, i935PATENT OFFICE viscoslME'rEa melma Powie, Bungie. N. Y.. wiener usierungA l y Engine Company, Buffalo, NfY.

, Applieauen peeember 171, ms, serlaiNe. 101,767

is claims. (circs-11) This invention relates to apparatus for themeasuring and indication of viscosity or rate of flow of liquids.

The objects of this invention are to provide an apparatus of this kindbymeans of which. vis'- cosity or uidity of the liquid can be accuratelyindicated; also to provide an apparatus of this ing from temperaturevariations of liquids can be eliminated; also to provide an apparatus ofthis kind which is usable in connection with liquids differing widely inviscosity; also to provide an apparatus of this kind of 'improvedconstruction which can be easily manufactured andthe vparts of which arereadily accessible for adjustment, inspection and repairs; also toimprove the construction of apparatus of this kind in other respectshereinafter specied. l In the accompanying drawings:

Fig. 1 is a side viewof a viscosity device em bodying this invention.

y Fig. 2 is'a transverse sectional elevation of the ,q

housing of the apparatus on line2-2, Fig. 1.

` Fig. 3 is a section thereof,on line 3 3, Fig. 2.

Fig. 4 is a sectional view thereof, on line #-4,1

Fig. 1.

Fig. 5 is a' fragmentary sectional view thereof, on line 5-5, Fig. 3.

The apparatus embodying the inventionV is illustrated in Fig. 1 forapplication directly to 4a conduit or pipe A carrying the liquid whoseviscosity or rate of flow is to be determined. The pipe or conduit A,for example, may be a part of an oil conduit carrying fuel oil to'aburner,

or it may carry any other liquid forany purpose. y

In the preferred embodiment of my invention, I havel provided a singlehousing, such for example as a casting, which forms a part ofthe conduitand in which the viscosity measuring means are arranged. It will beunderstood, however, that it is not intended -to limit the invention touse in connectionwith a housing of this kind, since obviously the liquidconducting means may be formed separately from the 'viscosity de-.termining means.

'Ihe frame or housing of the instrument as shown in the drawings`includes a tubular or cylindrical conduit portion; III forming apart ofa housing 1? of the instrument, and at opposite ends of the tubular partI0 ilanges b may be provided which are adapted to cooperate with anges asecured to the tube or conduit A, bolts I I serving` to connect theseilanges so that the tubular portion I0 of the housing formssubstantially a part of the conduit A..

The tubular ory cylindrical portion of the housing B is provided in aside thereof with an aperture I4 through which liquid may be withdrawnan upright tubular passage I8 which is provided with a graduatedaperture for controlling the amount of liquid which is withdrawn fromthe body of liquid in the tubular part IIlof the instrument. Preferably,the aperture is formed in a metering plug I9 suitably secured to thehousing in the aperture I8 so as to be readily removable and replaceableby another plug. It will be understood that the metering aperture can beformed in the housing B itself, but preferably it is formed in aremovable plug so that this plug can be replaced by another plug in casean spel.- ture becomes enlarged due to wearing away of the metal.surrounding the aperture. Furthermore,

when used on different liquids it may be desirable to provide aperturesof dilerent sizes.

'I'he aperture in the plug I 9 discharges liquid into a constantpressure chamber 20 formed in a part of the `housing or casing B,although, if desired, the constant pressure chamber and other parts ofthe instrument may be located in an- 'other housing separate from thetubular member III. .The constant pressure chamberis provided at theupper portion thereof with a removable cover or head 2| 'secured inplace by means -purposes hereinafter described.

In order to measure the viscosity of the liquid in the conduit A, theliquid in the constant pressure chamber should be maintained at apressure as near uniform as possible, and materially,

below the pressure of the liquid in the conduit A. Any suitable meansmay be provided for maintaining this reduced or differentiated pressureconstant. In the construction shown. a relief or unloading valve 25l isemployed which operates in conjunction with the metering plug |9 toproduce in the chamber 20 a constant pressure materially lower than thatin the conduit |0. This relief valve is arranged in a passage or channel26 formed in the housing B and extending downwardly froms the lower partof theconstant pressure chamber 29 to an atmospheric chamber or space21, which in the construction shown, is formed in adownwardly extendingpart 28 of the housing of the instrument. 'I'his extension 28 may beprovided with a vent opening 29 to insure that atmospheric pressure willprevail in the chamber 21. 'Ihe extension 28 of the housing may beconnected by any suitable coupling to a discharge pipe 30 by means ofwhich liquid discharged into the atmospheric chamber 21 may be conductedto a sump or container, not shown.

The discharge passage 26 in the housing is provided with a tapering seat32 for the valve 25il and preferably the seat has a very gradual taperso that considerable movement of the valve 25 is required to produce amaterial change in the opening of' this valve. The valve seat ispreferably formedin a cylindrical or tubular part 33 secured in thehousing of the instrument in the channel or passage 26. The valve, inthe construction shown, is connected to the. lower end of a stem 34which extends upwardly through the passage 26 into'the constant pressurecham- --ber 20.

In viscosity measuring instruments as heretofore made, the relief orunloader valve was yieldingly urged toward its closing position by meansof a spring. I have found, however, that a spring 4or similar yieldingmeans alone doesv not assure a constant pressure within the chamber 20,since the temperature of the liquid in the chamberhas a material effectupon such pressure. If, for ex` ample, the liquid is at a lowtemperature, it becomes correspondingly more viscous and slower flowingand consequently the same opening of the valve 25a will not result in adischarge of the' same quantity of liquid as would happen, if the liquidwere of a higher temperature and more f freely flowing, and failure todischarge liquid at the required rate results in the building up of a 7higher pressure within the chamber 2|). Such variations in pressurewould result in incorrect indications of viscosity by the instrument.

I have consequently provided means for compensating for diiferences intemperature of the liquid whose viscosity is to be measured, forexample, by providing for an increased dischargeA sion. The inner 4endof each coil may be suitably connected with the valve stem 34 and thethermostatic coils are so arranged that as the temperature of the liquidbecomes lowered, less up- .ward force is exerted on the valve, so thatthe valve opening is increased by the pressure of 1iq' uid in theconstant pressure chamber as the temperature of this liquid decreases.Consequently, by the correct design and adjustment of f these coils, thepressure within the chamber-29 may be kept constant, in spite ofvariations in temperature of the liquid. i

In theparticular mechanism illustrated in the accompanying drawings, theinner ends of the two spiral thermostatic springs 35 are rigidly securedto a rod or shaft 38 and between the coils, an arm 39 is rigidly securedto the rod or shaft, for example, by means of a key 40, Fig. 5. This armis adjustably connected to an extension 4| thereof which in turnconnects with one end of a link 42the other end of which connects withthe valve stem 34.

The acustable connection between the arm 39 and its extension 4| is madefor the purpose of adjusting the force exerted by the spring on thevalve stem. Any suitable connection may be employed, and in theconstruction shown, the arm 39 and its extension 4| are connected bymeans of a, clamping bolt 44, which, when released, acts as a pivotalconnection between the arm 39 and extension 4|. The arm 39 is providedwith a toothed segment 45 which may be formed integrally therewith orsecured thereto. The toothed segment 45 engages with a worm or screw 4S,journalled in the extension 4| of the arm and having a slotted head 41by means of which the Worm or screw can easily be turned by means of ascrew driver. It will be obvious that by turnlng the worm or screw 46,the extension 4| is swung about its pivotal connection 44 with'the arm39, and consequently, the arm 39 and extension 4| may be adjustedrelatively to each other to control the amount of force exerted by thespring's 35 on the valve stem 33. If the arm and its extension have beenset into the. desired relation to each other, these two parts may belocked against relative movement-by turning a slotted end 43 oftheclamping bolt, one end of which is screw threaded and engages witha'corresponding thread in one part of the bifurcated end 49 of theextension 4|, Aso that the two parts of the bifurcated portion may beclamped against the opposite sides of the arm 39. y l

Because of the relatively high pressure of the liquid in the tube orconduit I0, liquid will enter the constant pressure chamber 20 in theform of a jet throughI the orifice in the metering plug I9, which jetwill impinge against the lid or cover 2| and will be splashed toward thecoils 35 so that these coils will always be subjected to the temperatureof liquid entering the constant temperature chamber. AnyV other meansmay be provided 4for producing suitable circulation of liquid in theconstant pressure chamber so as to subject the coils 35 to thetemperature of liquid; the viscosity of which is to be measured.

The measurement of viscosity of the liquid may be effected in anysuitable or desired manner. In the construction shown for this purpose,the

'lower portion or base of the constant pressure vchamber 20 is providedwith a, downwardly extending passage 50, the upper end of whichterminates in the constant pressure chamber and the lower end of whichterminates in 'the atmospheric pressure space 21. The upper part of thispassage 59 may be provided with `another metering plug 5| removablysecured in the upper end -of the-passage and having an aperture of thedesired size. TheV passage 50 also preferably contains acapillarychannel or resistance tube 52 of definite internal diameter andlength, the upper' end ofnwhich may be arranged adjacent the meteringplug and the-lowerV end of which terminates in the atmospheric pressurespace. Between the upper end of the capillary channel or tube 52 and themetering plug 5I, the passage I is intercepted by'a; laterally extendingpassage or duct 54, one end of which communicates with the duct 50, andthe other end of which extends td the exterior of the housing and isprovided wit'n a threaded end portion '53 with which a pressure gauge 55may be connected. This gauge may be of the Bourdon type. or, if desired,any other type of pressure indicator may be employed. It will beunderstood that the pressures indicated on the gauge 55 will be thoseresulting from the difference in the rate of flow of liquid throughthesmall orifice in the plug 5l and through the resistance tube Aor channel52. The gauge may be calibrated so as to read directlyl inaybolt secondsor any other measurement of viscosity or rate of iiow. If the viscosityof a slow flowing liquid is to be measured, such liquid in,its slowpassage through the capillary or resistance tube, under constantpressure causes a relatively high static pressure within the lateraltube 5I and consequently, a high reading on the' pressure gauge 55,while a less viscous liquid -owing more rapidly lunder the same pressureresults in a correspondingly lower reading.

Preferably, the device -is also provided with" means for interruptingthe flow of liquid from inner end of the rod 50 closes the aperture I4 1and thus interrupts the ow of liquid to the measuring device.

Thel device described'has Athe advantage that it can be located in suchclose proximity to the pipe line A that there is substantially nodifference in temperature of the i'luid in thel tube I0 and that passingthrough the apertured plug/'5I and resistance tube 52. Consequently, thereading on the pressure gauge will not contain any error, due to suchtemperature change. 'I'he in-V strument described also has the advantageof being more accurate than other instrumentsv heretofore made, in thatdifferences in temperature of the liquid do not affect the pressure inthe constant pressures chamber 20, so that any error due to this causeis eliminated in my improved instrument. The instrument is also s'oconstructed thatall parts of it are readily accessible for inspections,adjustments or repairs.

In order to adjust the instrument for the desired pressure in theconstant pressure chamber, it is only necessary to remove the plug 25and attach a pressure gauge thereto. In order to obtain the correctpressure, a screw driver can be inserted through the threaded aperture24 to turn the worm 46 and the clamping screw 48. The instrument is alsoreadily adaptable for measuring viscositiesl of liquids diiferinggreatlyin thin rates of ow by replacing the plugs I9 and 5I by plugs havingorices of different sizes and by replacing the resistance tube by a tubeof different resistance to ow. 'I'he instrument is so constructed` thatall parts thereofare readily accessible for adjustment, replacement, or

repairs.

The instrument described makes it possible at all times to determine therate of flow of liquid in the pipe A, regardless of changes in pressureand temperature of the liquid, and the device is Atially constantpressure, temperature responsive means for urging said relief valve intoits closing position, said means being in-direct contact with the liquidin said constant pressure chamber to cause said means to exert lessforce on said valve when the liquid is at a lower temperature than whenit is at a higher temperature, to modify the operation of said reliefvalve to vary the discharge of liquid from said constant pressurechamber to compensate for temperature changes ,of said liquid, andviscosity measuring means to which liquid is discharged from saidchamber.

2. Invan instrument for measuring viscositya constant pressure chamberhaving an inlet for admitting liquid thereto from a supply of saidliquid at a higher pressure, a relief valve for discharging excessliquid from said chamber to maintain the liquid in said chamber at asubstantially constant pressure, and a bi-metallic thermostatic springarranged in said chamber and subjected to the temperature of the liquidand exerting a yieldingforce on said relief valve to urge the same intoclosing position, said force beingA varied in accordance with thetemperature of the liquid.

' 3. In an instrument for measuring viscosity, a

constant pressure chamber having an inlet for `admitting liquid theretofrom a supply of said liquid at a higher pressure, a relief valve for-Athe same into closing position, said force being varied inaccordancewith the temperature of the liquid, and an adjustable connection betweensaid spring and said valve for varying the force exerted by said springon said valve. i

4. In an `instrument for measuring viscosity, a`

constant pressure chamber having an inlet for admitting liquid theretofrom a supply of said liquid at a higher pressure, a relief valve fordischarging excess liquid from said chamber to maintain the liquid` insaid chamber at a substantially thermostatic spiral spring arrangedWithin said chamber and having one end thereof secured to a fixed partof said instrument, aI rod to which the other end of said spring issecured, and anad- Justable connection between said rod and said valve,said spring exerting a yielding force on said valve which diiersinaccordance with differences in temperature of the liquid in saidchamber.

5. In an instrument for measuring viscosity, a constant pressure chamberhaving an inlet for' admitting liquid thereto from a supply of saidliquid at a higher pressure, a relief valve for discharging excessliquid from said'chamber to maintain the liquid in' said chamber at asubstantially constant pressure, a spring arranged constant pressure, abi-metallic within said chamber and having one end thereof secured to afixed part of said instrument, a rod to which the other end of saidspring is secured, an arm extending outwardly from said rod and providedat its outer end with a gear segment, a second arm pivotally connectedwith said first arm, aworm journalled in said second arm and meshingwith said gear segment for adjusting said arms relatively to each cher,and a connection between said second arm and said valve for transmittinga yielding force to said valve in a direction tending to move the sameinto closing position.

6. In an instrument for measuring the viscosity of a liquid, thecombinationof a housing having a substantially unobstructed conduitformed therein through which the liquid, the viscosity of a part ofwhich is to be measured, flows, aconstant pressure chamber also formedin said housing, a passage in said housing connecting said conduit andsaid constant pressure chamber for conducting a small -portion of liquidfrom said conduit to said constant pressure chamber, relief means fordischarging excess liquid from said constant pressure chamber tomaintain a constant pressure in said chamber lower than the pressure insaid conduit, and viscosity measuring means carried by said housing andthrough which liquid from said constant pressure chamber is discharged.

7. In an instrument for measuring iscosity of a liquid flowing in aconduit, the com ination of a housing having Ia substantiallyunobstructed passage forming a portion of said conduit, a constantpressure chamber arranged in said housing, a second passage leading fromsaid iirst passage to said constant pressure chamber and through which asmall portion ofllquid from said first passage may flow, a relief valvethrough which liquid may be discharged from said constant pressurechamber, means arranged within said constant pressure chamber forcontrolling Y pressure chamber also formed'in said housing, a

passage in said housing connecting said conduit and said constantpressure chamber for conducting a small portion of liquid from saidconduit to said constant pressure chamber, relief means for dischargingliquid from said constant pressure chamber to maintain a constantpressure in said chamber lower than the pressure in said conduit,

a passage for conducting liquid out of said constant pressure chamber,and apertured plugs removably secured in said inlet and outlet passagesof said constant pressure chamber for controlling the quantity of liquidilowing through said.

passages.N

9. In an instrument for measuring viscosity of a liquid, the combinationof a housing having a substantially unobstructed passage through whichthe liquid, the viscosity of a part of which is to be' measured, flows,a constant pressure chamber in liquid flowing in said firsv passage tosaid chamber, means for maintaining the liquid in said chamber at aconstant pressure, means for withdrawing liquid from said chamber todetermine the viscosity thereof, and a valve for closing said secondpassage tol interrupt the operation of said instrument. 1 .Y

10. In an instrumentfor measuring viscosity of liquids, the combinationof a housing having a substantially unobstructed passage for the mainbody of the liquid, the viscosity of a part of which is to be measured,a constant pressure chamber in saidhousing, a passage connecting saidfirst pheric pressure space formed in said housing and into which saidunloading means and said discharge .passage discharge liquid.

11. In an instrument for measuring viscosity of a liquid, thecombination of a housing having a substantially unobstructed passagethrough which the liquid, the viscosity of a part of which is to bemeasured, flows, a constant pressure chamber in said housing, avgraduated passage leading from said first mentioned passage to saidconstant pressure chamber to conduct a small part of the liquid flowingin said first passage to said chamber, means for maintaining a constantpressure in said chamber and means for withdrawing liquid from saidNAchamber to determine the viscosity thereof.

12. In an instrument for measuring viscosity, a

vns

constant pressure chamber having an inlet Ior A admitting liquid theretofrom a supply of said liquid at a higher pressure, a relief valve fordischarging excess liquid from said chamber to maintainthe liquid insaid chamber at a substantially constant pressure, and thermostaticmeans in actual contact with the liquid within the constant pressurechamber for modifying the operation of said relief valve to vary thedischarge of liquid from said chamber to compensate for temperaturechanges of saidi liquid.

' 13. In an instrument for measuring viscosity, a constant pressurechamber having an inlet for admitting liquid thereto from a supply ofsaid liquid at a higher pressure, a passage from said chamber forliquid, the viscosity of which is to be measured, a second passagethrough -which liquid may be discharged from said chamber, meansresponsive to 4pressure in said constant pressure chamber forcontrolling ow through said second passage to maintain the liquid insaid chamber at a Asubstantially constant pressure, and thermostaticmeans in actual contact with the liquid in the constant pressure chamberfor varying the/extent to which said second passage'is opened for thedischarge of liquid to compensate for temperature changes of saidliquid.,

14. In an instrument for measuring viscosity, a constant pressurechamber having an inlet for admitting liquid thereto from a supplyv ofsaid liquid at a higher pressure, a relief valve for discharging excessliquid from said chamber to maintain the liquid in said chamber at asubstantially constant pressure, yielding means for urging said valveinto its closing position, and

thermostatic means acting in conjunction with said yielding means todecrease the extent to which said yielding means urge said valve into pin actual contact with the liquid within the con.

' tending to increase thel -aoiasso 1 closing position whenA thetemperature of the` liquid is'reduced, said means being vstant pressurechamber 15. In an instrument .for viscosity. a

constant pressure chamber having an inlet for admitting liquid theretofrom a supply oi said liquid at a higher pressure. a relief valve-fordischarging excess liquid from said chamber to maintainthe liquid insaid'chmberat a subthe constant pressure in said-chamber, includingthermostatic means in actual contact with the liquid within saidconstant pressure chamber and unloading of said cham-"- ber hen theliquid becomes colder, and-viscosity 1 to whichliquld -is discharged im'f1 In'an' viscosity, a4

cassant pressure enema-esmas: an met :er

liquidthereto -fromia supply or said 'liquid 'at a higher pressure, arelietivalve for disliquid from to maintain the liquid in said chamberat a substantiallv constant pressure, and a bi-metallic thermostaticspring in actual contact with the liquid within the constant pressurechamber and acting on said reliefvalve to exert a yielding force on saidvalve to move the same into closing position, which force is increasedas the temperature o! the liquid increases.

18. In an instrument for measuring the viscosity of a liquid, thecombination of a chamber in which a `small portion of said liquid ismaintained at a controlledpressure, a relief valve acted upon by thepressure within said chamber and yieldingly urged vinto closing positionfor maintaining the liquid in said chamber at a substantially constantpressure, and thermostatic means in ,actual contact with the'liquidwithin the constant pressure chamber and acting on said valve to varythe torce exerted thereon in accordance with changes in temperature, soas to allow the valve to openvto a greaterextent when the liquid is coldthan when" itis warm.

1,9. In an instrument for measuring viscosity ofV aliquid and 'having aconstant pressureA chamber into whichliquid is` admitted from a. supplyof said liquid at a higher pressure, 'unloading means for dischargingexcess liquid from said chamber,

i and a iii-metallic thermostatic coil spring in actual contact with theliquid within the constant pressure chamber for modifying the operationof ture 'changes of the liquid to produce constant RICHARDPOWIS.

